Cyclists’ hearts: can you be so fit that you die?

Why have dozens of endurance athletes died in their sleep over the last few decades? How can a cyclist’s heart rate be slower than an elephant’s? Elite cyclists have such extreme physiology and such abnormal cardiovascular systems that their hearts beat less than 30 times a minute. Combined with performance-enhancing drugs that makes their blood thick and gloopy with red blood cells, this spells a recipe for disaster. The legendary ’Il Pirata’, Marco Pantani, had to wake up in the night and cycle on a sta